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      <title>A、B、C三个服务，A调B，B调C，C出异常挂了怎么办 - 交互式测验</title>
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        .option-item.selected {
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            border-color: #4a90e2;
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        .quiz-footer {
          padding: 20px 30px;
          display: flex;
          justify-content: space-between; /* 将按钮分布在两侧 */
          align-items: center;
          min-height: 65px; /* Reserve space */
        }

        .nav-btn {
          background-color: #4a90e2;
          color: white;
          border: none;
          border-radius: 8px;
          padding: 10px 20px;
          font-size: 16px;
          font-weight: 500;
          cursor: pointer;
          transition: background-color 0.2s ease, transform 0.2s ease;
          box-shadow: 0 4px 12px rgba(0,0,0,0.15);
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        .result-box {
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            background-color: #d4edda;
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        .explanation-text {
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        .source-text {
            font-style: italic;
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        .final-score-container {
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            text-align: center;
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        .final-score-container h2 {
            margin-top: 0;
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            padding: 20px;
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    <body>
      <div class="main-wrapper">
          <div class="quiz-container">
            <div class="quiz-header">
              <h1>A、B、C三个服务，A调B，B调C，C出异常挂了怎么办 - 交互式测验</h1>
              <p>检验你对文档内容的理解程度</p>
            </div>
            <div id="quiz-content">
                <div class="quiz-body">
                    <div class="progress-bar">
                        <div id="progress-indicator"></div>
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                    <div id="question-container">
                      <p id="question-text"></p>
                      <ul class="options-list" id="options-list"></ul>
                    </div>
                    <div id="result-container"></div>
                    <div id="hint-container" class="hint-container"></div>
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                <div class="quiz-footer" id="quiz-footer">
                  <button id="prev-btn" class="nav-btn">上一题</button>
                  <button id="hint-btn" class="nav-btn" style="background-color: #ffc107; color: #333; box-shadow: 0 4px 12px rgba(255,193,7,0.3);">提示</button>
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      <script>
        const quizData = [
  {
    "question": "在微服务架构中，当一个下游服务（如Service C）响应缓慢或失败时，“断路器模式”（Circuit Breaker Pattern）最核心的作用是什么？",
    "options": [
      "自动重试对失败服务的调用，直到成功为止。",
      "防止故障向上游服务蔓延，避免产生级联故障。",
      "确保消息最终能被下游服务处理，即使它暂时离线。",
      "为服务间的通信提供加密，保证数据安全。"
    ],
    "correctAnswerIndex": 1,
    "explanation": "断路器模式的核心目标是“防止级联故障”。当一个服务持续失败时，断路器会“跳闸”（打开），阻止后续的请求直接发往这个故障服务，而是立即返回一个错误或执行降级逻辑。这保护了调用方（上游服务）的资源，避免其因等待一个无响应的服务而被耗尽，从而防止了整个系统的连锁崩溃。",
    "source": "文档中「1. 使用断路器模式」部分",
    "hint": "文档中提到，该模式是“一种防止服务之间连锁反应的模式”并且其优点之一是“防止级联故障”。"
  },
  {
    "question": "根据文档，「重试机制」最适合处理哪种类型的服务调用失败？",
    "options": [
      "由于下游服务存在永久性的逻辑错误（Bug）导致的失败。",
      "由于临时的网络波动或服务短暂不可用造成的失败。",
      "需要将服务间调用解耦，以提高系统弹性的场景。",
      "上游服务收到了格式错误的请求数据。"
    ],
    "correctAnswerIndex": 1,
    "explanation": "重试机制的价值在于处理那些“暂时性”或“间歇性”的故障。例如，网络瞬间抖动、目标服务正在重启等。对于这些问题，短暂延迟后重新尝试调用很可能会成功。但对于永久性错误（如代码缺陷、数据库损坏），重试只会徒劳地增加系统负载。",
    "source": "文档中「2. 使用重试机制」部分",
    "hint": "思考一下什么样的问题是“再试一次”就有可能解决的？文档中明确指出，重试机制可以“处理临时的网络故障或服务暂时不可用的情况”。"
  },
  {
    "question": "在进行服务间远程调用时，设置合理的「超时」值主要能带来什么好处？",
    "options": [
      "当目标服务不可用时，提供一个预定义的替代响应。",
      "保证消息在生产者和消费者之间可靠传递。",
      "避免当前线程因等待一个无响应的服务而被长时间占用，从而快速释放资源。",
      "自动记录每次服务调用的详细日志，用于事后分析。"
    ],
    "correctAnswerIndex": 2,
    "explanation": "超时设置的核心作用是为资源设置一个“止损线”。在分布式系统中，一个服务的延迟可能导致调用它的服务也延迟，形成连锁反应。通过设置合理的超时，调用方可以避免无限期地等待，快速失败并释放线程等宝贵资源，从而保护自身服务的可用性和系统的整体响应速度。",
    "source": "文档中「3. 使用超时设置」部分",
    "hint": "文档中提到该策略的一个优点是“避免请求长时间挂起”。"
  },
  {
    "question": "文档中提到的“异步调用和消息队列”方案，其在提升系统容错性方面最主要的优势是什么？",
    "options": [
      "在服务调用失败时，立即返回一个预设的默认值。",
      "将服务间的直接依赖关系解耦，使得一个服务的故障不会立即阻塞另一个服务。",
      "对失败的同步调用进行多次自动重试。",
      "监控服务的健康状况并及时发出警报。"
    ],
    "correctAnswerIndex": 1,
    "explanation": "使用消息队列（如RabbitMQ、Kafka）进行异步通信，核心优势在于“解耦”。生产者服务只需将消息发送到队列即可完成任务，而无需关心消费者服务当前是否可用。即使消费者服务宕机，消息也会暂存在队列中，待其恢复后再进行处理。这种方式极大地增强了系统的弹性和可扩展性。",
    "source": "文档中「4. 使用异步调用和消息队列」部分",
    "hint": "此方案的优点之一是“解耦服务”，想一想“解耦”意味着什么？"
  },
  {
    "question": "当C服务不可用时，系统不直接报错，而是返回一个缓存的旧数据或一个通用的默认响应。这种策略在文档中被称为什么？",
    "options": [
      "重试机制 (Retry)",
      "服务降级 (Service Degradation)",
      "超时设置 (Timeout)",
      "日志监控 (Logging and Monitoring)"
    ],
    "correctAnswerIndex": 1,
    "explanation": "服务降级是指在系统核心组件或依赖服务出现问题时，为了保证核心功能的可用性，暂时牺牲一些非核心功能或提供一个有损的、简化的服务。文档中的描述——“提供一个预定义的替代方案或返回默认值”，正是服务降级的典型实现。",
    "source": "文档中「6. 服务降级」部分",
    "hint": "文档中描述了一种策略，它“可以在C服务不可用时，提供一个预定义的替代方案或返回默认值”。"
  },
  {
    "question": "在Hystrix的Java代码示例中，`@HystrixCommand(fallbackMethod = \"fallbackMethod\")` 这个注解同时体现了文档中提到的哪两种容错模式？",
    "options": [
      "重试机制与超时设置",
      "异步调用与日志监控",
      "断路器模式与服务降级",
      "消息队列与超时设置"
    ],
    "correctAnswerIndex": 2,
    "explanation": "这个注解是Hystrix库的核心功能。`@HystrixCommand` 本身就封装了断路器的逻辑（以及超时、限流等）。而其 `fallbackMethod` 属性则明确指定了当主逻辑（调用C服务）失败或断路器打开时，应该执行的备用逻辑。这个备用逻辑就是一种典型的“服务降级”实现。",
    "source": "文档中「1. 使用断路器模式」部分 (该部分的示例代码直接展示了降级实现)",
    "hint": "这个注解本身代表了一种核心的容错模式，而它的一个关键参数指向了另一种当主逻辑失败时启动的策略。"
  },
  {
    "question": "为了能“及时发现问题”并“便于问题排查”，文档推荐使用哪一类工具组合？",
    "options": [
      "Hystrix 和 Resilience4j",
      "RabbitMQ 和 Kafka",
      "Prometheus, Grafana, ELK Stack",
      "RestTemplateBuilder 和 RabbitTemplate"
    ],
    "correctAnswerIndex": 2,
    "explanation": "文档明确指出，“日志记录和监控可以帮助你了解服务的健康状况，及时发现问题”。并列举了实现这一目标的常用工具：Prometheus（用于指标收集和告警）、Grafana（用于数据可视化展示）以及ELK Stack（用于日志的收集、存储和分析）。这些工具共同构成了强大的可观测性（Observability）平台。",
    "source": "文档中「5. 日志记录和监控」部分",
    "hint": "文档在介绍“日志记录和监控”时，直接列出了一些推荐的实现工具。"
  }
];
        console.log("Quiz Data:", JSON.parse(JSON.stringify(quizData))); // 添加这行用于调试，以可展开的JSON格式输出
        
        let currentQuestionIndex = 0;
        let score = 0;
        // 存储每个问题的回答状态
        const userAnswers = new Array(quizData.length).fill(null); 

        const questionTextEl = document.getElementById('question-text');
        const optionsListEl = document.getElementById('options-list');
        const resultContainerEl = document.getElementById('result-container');
        const quizContentEl = document.getElementById('quiz-content');
        const progressIndicatorEl = document.getElementById('progress-indicator');
        const prevBtn = document.getElementById('prev-btn');
        const nextBtn = document.getElementById('next-btn');
        const hintBtn = document.getElementById('hint-btn');
        const hintContainerEl = document.getElementById('hint-container');

        function loadQuestion() {
          resultContainerEl.innerHTML = '';
          optionsListEl.innerHTML = '';
          hintContainerEl.style.display = 'none'; // 隐藏提示
          
          if (currentQuestionIndex >= quizData.length) {
            showFinalScore();
            return;
          }

          updateProgress();

          const currentQuestion = quizData[currentQuestionIndex];
          questionTextEl.textContent = `(${currentQuestionIndex + 1}/${quizData.length}) ${currentQuestion.question}`;
          
          currentQuestion.options.forEach((optionText, index) => {
            const li = document.createElement('li');
            li.className = 'option-item';
            li.textContent = optionText;
            li.dataset.index = index; // Store index in a data attribute
            // 如果这道题已经回答过，恢复状态
            if (userAnswers[currentQuestionIndex] !== null) {
                if (index === userAnswers[currentQuestionIndex]) {
                    li.classList.add('selected');
                }
            }
            optionsListEl.appendChild(li);
          });

          // 如果已经回答过，直接显示结果
          if (userAnswers[currentQuestionIndex] !== null) {
              const isCorrect = userAnswers[currentQuestionIndex] === currentQuestion.correctAnswerIndex;
              showResult(isCorrect, currentQuestion);
          }
          
          updateNavigationButtons();
          updateProgress();
        }

        function selectOption(optionIndex) {
            userAnswers[currentQuestionIndex] = optionIndex;
            const currentQuestion = quizData[currentQuestionIndex];
            const isCorrect = optionIndex === currentQuestion.correctAnswerIndex;

            // 重新计算分数
            score = userAnswers.reduce((acc, answer, index) => {
                return answer === quizData[index].correctAnswerIndex ? acc + 1 : acc;
            }, 0);

            showResult(isCorrect, currentQuestion);
            updateNavigationButtons();
        }
        
        function updateProgress() {
            const answeredQuestions = userAnswers.filter(answer => answer !== null).length;
            const progressPercentage = (answeredQuestions / quizData.length) * 100;
            progressIndicatorEl.style.width = `${progressPercentage}%`;
        }
        
        function updateNavigationButtons() {
            prevBtn.style.display = 'block';
            nextBtn.style.display = 'block';
            hintBtn.style.display = 'block'; // 显示提示按钮

            prevBtn.disabled = currentQuestionIndex === 0;
            nextBtn.disabled = false; // 最后一题时，下一题按钮不禁用，而是用于显示报告
            nextBtn.textContent = (currentQuestionIndex === quizData.length - 1) ? '查看报告' : '下一题';
            
            // 如果当前问题没有提示，则禁用提示按钮并隐藏提示内容
            if (!quizData[currentQuestionIndex].hint) {
                hintBtn.disabled = true;
                hintContainerEl.style.display = 'none';
                hintContainerEl.textContent = ''; // 清除旧的提示内容
            } else {
                hintBtn.disabled = false;
            }
        }

        function showResult(isCorrect, questionData) {
            resultContainerEl.innerHTML = ''; // 清空之前的结果
            const resultBox = document.createElement('div');
            resultBox.className = `result-box ${isCorrect ? 'correct' : 'incorrect'}`;
            
            let html = `<h3>${isCorrect ? '回答正确！' : '回答错误'}</h3>`;
            if (!isCorrect) {
                html += `<p><strong>正确答案是：</strong> ${questionData.options[questionData.correctAnswerIndex]}</p>`;
            }
            html += `<div class="explanation-text">${questionData.explanation}</div>`;
            html += `<div class="source-text">来源: ${questionData.source}</div>`;
            
            resultBox.innerHTML = html;
            resultContainerEl.appendChild(resultBox);

            // 禁用所有选项的点击事件，并高亮正确/错误答案
            Array.from(optionsListEl.children).forEach((child, index) => {
                child.style.pointerEvents = 'none';
                // 高亮正确答案
                if (index === questionData.correctAnswerIndex) {
                    child.classList.add('correct'); // 需要添加CSS样式
                    child.style.backgroundColor = '#d4edda';
                    child.style.borderColor = '#c3e6cb';
                }
                // 如果选错了，高亮错误选项
                if (!isCorrect && index === userAnswers[currentQuestionIndex]) {
                    child.classList.add('incorrect'); // 需要添加CSS样式
                    child.style.backgroundColor = '#f8d7da';
                    child.style.borderColor = '#f5c6cb';
                }
            });
        }

        function goToNextQuestion() {
            if (currentQuestionIndex < quizData.length - 1) {
                currentQuestionIndex++;
                loadQuestion();
            } else {
                showFinalScore();
            }
        }

        function goToPreviousQuestion() {
            if (currentQuestionIndex > 0) {
                currentQuestionIndex--;
                loadQuestion();
            }
        }
        
        function showHint() {
            const currentQuestion = quizData[currentQuestionIndex];
            if (currentQuestion.hint) {
                hintContainerEl.textContent = currentQuestion.hint;
                hintContainerEl.style.display = 'block';
            } else {
                hintContainerEl.style.display = 'none';
            }
        }

        function showFinalScore() {
            document.querySelector('.quiz-body').style.display = 'none';
            document.getElementById('quiz-footer').style.display = 'none';

            const correctCount = score;
            const totalQuestions = quizData.length;
            const answeredCount = userAnswers.filter(a => a !== null).length;
            const wrongCount = answeredCount - correctCount;
            const skippedCount = totalQuestions - answeredCount;
            const accuracy = totalQuestions > 0 ? Math.round((correctCount / totalQuestions) * 100) : 0;
            const errorRate = totalQuestions > 0 ? Math.round((wrongCount / totalQuestions) * 100) : 0;

            const finalScoreHtml =
                '<div class="final-score-container">' +
                '<h2>答题报告</h2>' +
                '<div class="score-summary">' +
                '<div class="score-card">' +
                '<h3>得分</h3>' +
                '<p>' + correctCount + ' / ' + totalQuestions + '</p>' +
                '</div>' +
                '<div class="score-card">' +
                '<h3>正确率</h3>' +
                '<p>' + accuracy + '%</p>' +
                '</div>' +
                '<div class="score-card">' +
                '<h3>错误率</h3>' +
                '<p>' + errorRate + '%</p>' +
                '</div>' +
                '<div class="score-card score-details">' +
                '<table>' +
                '<tr><td>正确</td><td>' + correctCount + '</td></tr>' +
                '<tr><td>错误</td><td>' + wrongCount + '</td></tr>' +
                '<tr><td>未答</td><td>' + skippedCount + '</td></tr>' +
                '</table>' +
                '</div>' +
                '</div>' +
                '<div class="report-actions">' +
                '<button id="review-btn">回顾测验</button>' +
                '<button class="primary" onclick="location.reload()">再试一次</button>' +
                '</div>' +
                '</div>';

            let reportEl = document.querySelector('.final-score-container');
            if (reportEl) {
                reportEl.remove();
            }
            quizContentEl.insertAdjacentHTML('beforeend', finalScoreHtml);
            document.getElementById('review-btn').addEventListener('click', reviewQuiz);
        }

        function reviewQuiz() {
            const reportEl = document.querySelector('.final-score-container');
            if (reportEl) {
                reportEl.remove();
            }

            document.querySelector('.quiz-body').style.display = 'block';
            document.getElementById('quiz-footer').style.display = 'flex';
            
            currentQuestionIndex = 0;
            loadQuestion();
            updateNavigationButtons(); // Ensure nav buttons are correctly displayed
        }

        // Event Delegation for options
        optionsListEl.addEventListener('click', (event) => {
            if (event.target && event.target.matches('li.option-item')) {
                // Check if the question has already been answered
                if (userAnswers[currentQuestionIndex] === null) {
                    const selectedIndex = parseInt(event.target.dataset.index, 10);
                    selectOption(selectedIndex);
                }
            }
        });

        prevBtn.addEventListener('click', goToPreviousQuestion);
        nextBtn.addEventListener('click', goToNextQuestion);
        hintBtn.addEventListener('click', showHint);
        
        // 初始加载
        loadQuestion();
      </script>
    </body>
    </html>
  